1. Field of the Invention
The present invention relates to a cylindrical jacket, such as a fire hose, a shape-keep hose, a water absorption hose and an oil supply hose, a jacket hose, and a suction hose, and an apparatus for manufacturing the cylindrical jacket.
2. Description of the Related Art
A fire hose is generally made liquid-tight by forming a lining layer made of rubber or synthetic resin on the inside surface of a cylindrical jacket. Namely, a jacket is formed by weaving warp and weft fibers in a cylindrical form by a cylindrical weaving machine, and forming a lining layer on the inside surface of the jacket.
A fire hose is strongly demanded to be flexible and lightweight, and the lining layer tends to become thin. However, if the lining layer is made thin, the texture (crossing) formed by the warp and weft becomes uneven on the inside surface of a jacket, and the uneven texture causes unevenness in the lining layer. This uneven lining layer causes resistance to the flow of water. Particularly, the resistance is increased by a projected rim generated by the weft in the circumferential direction (spiral direction) just like bellows.
In a conventional hose, a lining layer is provided on the inside surface of a cylindrical jacket, and projected rims are provided in the lining layer along the hose length direction (Patent Document 1, for example).
In another example of conventional hose, a lining layer is provided on the inside surface of a cylindrical jacket, and grooves are provided inside the lining layer along the hose length direction (Patent Document 2, for example).
In either example, generation of turbulence on the inside surface of a hose is controlled, a pressure loss is minimized, and a water flow speed is increased.
However, the thickness of a lining layer of a fire hose is approximately 0.5 mm in order to ensure flexibility and lightweight. If the lining layer thickness is increased by providing projected rims, the flexibility and lightweight cannot be ensured. Therefore, the height of projected rims must be set low. Further, when forming a groove in the lining layer, the groove depth is not deep as long as it formed in a lining layer of approximately 0.5 mm.
Therefore, even if a projected rim or a groove is formed in the lining layer along the central axis of a hose, it is insufficient to control the turbulence because a large unevenness like a bellows is generated by a weft. If the projected rim is made high or the groove is made deep by forming a thick lining layer, the flexibility and lightweight of a hose cannot be ensured. Further, if the lining layer is given additional processing, the cost is increased.
Patent Document 1: Jpn. Pat. Appln. KOKAI Publication No. 7-4569 (claims and FIG. 1)
Patent Document 2: Jpn. Pat. Appln. KOKAI Publication No. 2000-55247 (claims and FIG. 1)